This paper investigated the role of microemission characteristics of a diesel engine when CeRuO2 blended with diesel is used as a fuel. The major problem areas for combustion ignition (CI) engines are emissions. A novel microemulsion-based protocol was utilized to disperse the catalysts in the diesel fuel. The fuel was prepared comprising CeO2, Ce0.95Ru0.05O2, Ce0.9Ru0.1O2, and Ce0.8Ru0.2O2 by volume (0, 5, 10, and 20 mole%) was used in a CI engine. The catalyst microemulsion system remains stable upon its addition to the diesel fuel. The results show that the CI engine works well and the power outputs are steady running with the biodiesel blends at different loads. The acquired information were studied and found a decrease in HC, CO, NOx, and soot.